Lee Factory Crimp Die

[saddlebum]

Hey Veral,  I'm wondering what your experience/opinion is on Lee factory crimp dies. I have never used them but alot of people seem to think they are a necessity. Am I missing something? The roll crimp from RCBS dies seems to work fine,(if adjusted right), on my revolver loads. I am speaking of cast bullet revolver rounds. What are your thoughts about crimping for better ignition and proper grip on bullets? I have been adjusting my crimps from light to heavy according to my needs on different loads. Will a LFC die improve any aspect of my finished round? Is it good for holding heavy cast bullets in hot loads?   Thanks!!

[mousegun]

Veral will have the straight dope on this issue, but my own experience is this: the pistol caliber factory crimp die is a standard crimp die with a carbide sizing ring in it.  The idea is to resize the case after seating the bullet to factory case dimensions for easy chambering.

I found that once I had my cast bullets correctly sized for the bore at .432", this die would size the bullet down to .429" undersizing the bullet for the bore I had.  I sent the die back to Lee to have the carbide ring opened up to keep from resizing the bullet.  I works better, but still knocks about .001" off the bullet diameter.

Thick brass is not your friend with this die.
YMMV

(o)(-)
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[saddlebum]

mousegun;  Thanks for the info. When I was reading about the die on their website I was really skeptical about the whole idea of resizing for the reasons you mentioned. Even with the rifle FC dies they sell a "Bulge buster kit" to go with them to get rid of bulges in the case. So how does FC dies improve anything if you get bulges with them too?.......... Just trying to think things thru here. My standard RCBS dies form a tight grip on my bullets that you can see and feel. If I adjust my roll crimp die properly and set the lock ring, I have no problems. Sure I have over crimped before and had problems, but that was my fault and I fixed it. I can see the possible advantage of using them on my rifle loads that have bullets with no cannlures, maybe. But if the sizing die does what it's supposed to, I get a good tight friction fit on the bullet and don't need much of a crimp if any..........Thanks for your input!!

[gypsyman]

While the factory crimp die isn't bad, there are better ways. Look at what the serious benchrest shooters are doing. In single shot rifle's, or match guns, they don't crimp at all. The other ways to crimp,taper,roll, or profile, generally give you better accuracy, and case life. gypsyman

[Veral]

  The rifle and pistol Lee factory crimp dies are two completely different breeds of cat.

  The pistol die I can't say enough against to make me happy.  It isn't needed for cast in the first place and if it sized a loaded case and bullet to factory specs the brass loses it hold on the bullet and the crimp is all there is to hold a loose bullet.   It is actually only a standard crimp die with a sizer ring to ruin any rounds with oversize bullets, and can buckle brass the same as any crimp die will when rounds are crimped to deeply. Please don't use the lee factory crimp pistol dies, and be sure you never put my name with any recomendations of them.

  The rifle dies do not have the sizer die to reduce diameters.  Only a collet which applies the crimp with no force on the brass which would cause case buckling.  These are excellent for rifle ammo which needs to have the bullets locked in so they don't get driven deeper in the case while moving through the magazine.  i.e. Leverguns.  They allow one to taylor crimp many cast bullets of suitable diameter to suit the throating, magizine, and action for smooth feeding/chambering.  The crimp should be applied as lightly as possible and still prevent bullet setback.  Excessive crimp will shorten case life dramatically.  When using them with jacketed in long/worn throat rifles, accuracy can often be dramatically improved with short bearing bullets by applying a crimp near the center of the bullets bearing surface.  In this case the crimp should be applied deeply enough so a bullet will be a tight fit in the crimp of a fired case.  The crimp becomes a bullet centering guide to keep the rear of the bullet on center with the throat/chamber neck as it enters the rifling.  This centering is the only real advantage of crimping most rifle ammo, when the gun of interest doesn't have a magazine or action which can drive bullets down into the case during cycling.

[saddlebum]

Thanks Veral! You confirmed what I thought about the handgun dies. I can see what you are saying about the benefits of the rifle dies. Good info on tayloring the crimp/seating depth on cast bullets that have not been made to fit a particular rifle, or to maximize bullet stability/accuracy/feeding in a levergun. I may at some time want to experiment with one of my leverguns like my M-99 Savage to seat the bullet farther out than the cannlure to make it more accurate. I don't think I would see much benefit in my bolt actions since I always seat the bullets to just off the lands and I get a pretty tight fit in the case neck. If cast bullet molds are cut to fit the gun/throat then I don't know as I would need the FC die for that, especially if it has a crimp groove. The advantages you mentioned does show the real usefulness for these dies. Some things I hadn't thought of. I knew I was asking the right guy.   God Bless!!

[Veral]

  Saddlebum: 
  You miss understood what I was trying to say a little bit.
 
  The concept of improoving accuracy is valid in any rifle, and especially those with oversize chamber neck area or well worn throats.  For this type condition the object is to create a centering collet to hold the rear of the bullet on center, and when doing so, it is normally best to seat the bullet so it runs at least 1/16 inch before hitting the rifling.  Or, with short bearing bullets such as boat tails or light varmint type bullets, where the bullet base may barely be in the case by time the forward part of the bearing surface hits rifling, and it is impossible to seat up close to the rifling and still maintain case neck grip.  Always put the crimp well away from the ends of the bearing surface, as we want to keep the bearing strong at both ends.

[saddlebum]

Gottcha. Thank you Veral. I appreciate your help! Your the best! 

[docmagnum357]

I have found Lee factory Crimp dies great on rifle loads, Fine on Semi auto pistol loads, and they are not much good on cast bullet revolver loads.  Pretty much word for word with what Veral said.  I seldom crimp varmint loads, and i use 243 to 7mm Rem. for varmints.  If the bullet has a crimp groove, or cannelre, I crimp.  I crimp game weight ballistic tips, but the Lee Taper Crimp is better. 

[docmagnum357]

Lee used to claim the least run out of any dies, and i believe this was and may still be true, but everyone doesn't shoot varmint caliber rifles, and accuracy, in an absolute sense, isn't everything.  I wouldn't want to get a bullet stuck in the chamber of my 458 because of a poor grip on the bullet.  I wouldn't want to have the bullet set back after firing several rounds and having the bullet on the cartridge in the bottom of the magazine get shortened up by battering in the magazine either.  Both situations could cost you your life; not a good trade for even two moa of accuracy. I usualy keep two sets of dies for my 243, and 7mm mag, one for varmint loads, and one for game. Taper crimp varmint/target bullets/loads, and roll crimp game loads.Saves set up time, too.

[Veral]

  About the Lee claim of least runout of any dies.  -  If he was speaking of runout between inside diameter and outside, that may have been true, but it wouldn't matter.  If he was speaking of the different points inside a die, i.e. between neck and body, the claim was a smoke screen, as all of them are cut inside with a reamer and reamers don't cut with runout if a one piece reamer is used.  I cannot imagine any manufacturer cutting the inside of a die with several operations, for sake of time alone, but also because one of the first thing any macninest learns is the problems with runout when making a hole with several tools.